Railway traffic controlling apparatus



Oct. 11,1949.

| v. LEWIS RAILWAY TRAFFIC CONTROLLING APPARATUS 3 Sheets-Sheet 1 W M; a 1

NMMK

Filed Jan. 12 1946 5 Shee'ts-Sheet 2 IN V EN TOR.

L. V. LEWIS RAILWAY TRAFFIC CONTROLLING APPARATUS His ATTORNEY Llo I K Lewis.

m w u m kwwm m QRN Oct. 11, 1949.

Filed Jan. 12, 1946 N wwm L. V. LEWIS RAILWAY TRAFFIC CONTROLLING APPARATUS Oct. 11, 1949.

3 Sheets-Sheet 5 Filed Jan. 12, 1946 INVENTOR. Zloy 1 Lewis. BY

7' I I v ATTORNEY Patented Oct. 11, 1949 UNITED STATES PATENT oFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Lloyd V. Lewis, Pittsburgh, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application January 12, 1946, Serial No. 640,753

ment upon that shown in Fig. 1 of an application for Letters Patent of the United States, Serial No. 501,254, filed September 4, 1943, by Henry S. Young, for Railway traflic controlling apparatus, now Patent No. 2,420,579, issued May 13, 1947.

In the centralized traffic control system shown and described in this Young application, an absolute permissive block system controlled by continuous track circuits is provided for governing traflic movements in two directions over a stretch of single track railroad having passing sidings at spaced locations. The movement of traffic into the blocks is governed by head block signals, located at the opposite ends, and the blocks are divided into block sections, with intermediate signals for two directions located at the junctions of the sections. All of the signals for a block are controlled over a system of reversible line circuits in accordance with traffic conditions as manifested by the track relays of the adjacent block sections. The head block signals are made subject to manual control from a central point, such as a train dispatchers office, by the provision of a code type communication system, having field stations located at the block ends for receiving control codes transmitted from the ofiice, by which control relays for the signals are operated in accordance with the positions of signal levers at the ofiice, and by which traflic relays are operated to govern the direction of energization of the reversible line circuit system, in accordance with the position of a master directional relay at the office. The station apparatus of the code system also serves to transmit indication codes to the ofiice for indicating wayside conditions to the operator by the lighting of various lamps associated with a track diagram, and for imposing restrictions upon the issue of control codes by the operator. A feature of the indication system is the provision of a block indicator for each block for indicating the presence of a train at any point therein, controlled jointly by codes transmitted from both ends of the block which reflect the condition of different portions of the reversible line circuit system by which the signals are controlled.

2 The centralized traflic control system also includes provisions for releasing electric locks for outlying hand throw switches, by cooperation between the central oflice operator and the crew of a train, involving means for enabling the operator to set up the reversible line circuit system so as to permit a switch to be unlocked to enter the block from a side track only when the entire block is vacant, and to then proceed through the block in a selected direction under the protection of the signal system,

The principal object of my invention is to provide an improved system of traflic direction control for use in centralized traflic control of the type referred to, or for use in other systems having generally similar requirements, such as those employing cascade-connected reversible track circuits in place of line circuits, as shown, for example, in Letters Patent of the United States No. 2,344,333, issued March 14, 1944, to James J. Van Horn, for Railway traffic controlling apparatus, which patent was re-issued as No. 22,780, on Aug. 13, 1946.

The trafic direction controlling apparatus of my invention functions in such a manner that the control of the traflic relays at the ends of the blocks requires no special action by the operator, but is efiected as a result of the usual operations of reversing the signal lever for the head block signal which is to be cleared, followed by the operation of the associated code starting button whereby the transmission of a code for clearing the signal is initiated.

In the event the traflic direction set up is the opposite to that desired, but the block is unoccupied and all of the head block signals are at stop, as would be the case, for example, if the operator desired to authorize an eastbound train to enter a block which has just been vacated by a westbound train, the operations mentioned result first in the movement of the master directional relay at the ofiice to a position marking the desired traflic direction, and then in the transmission of control codes to both ends of the block whereby the traflic relays are operated to corresponding positions so as to reverse the direction of energization of the 3 clear in response to the energization of the line circuit system.

The wayside apparatus for outlying switch control includes an indication relay at the switch having contacts controlling the reversible line circuit system which when closed indicate that the switch is docked .in its normal position. To reverse the switch "topermit a train-to enter the main track, the crew of the train after securing permission from the centra1 office operator and removing a padlock or the like, open a v local circuit to release the switch indication relay, which relay upon releasing divides the line circuit system into two portions and connects a line relay at the switch location to each portion. When the operator grants permission to unlock the switch he also operates a switch llockalever to the right or left in accordance, with the direction of movement of the train, thereby operating the master directional relay in a corresponding direction, provided the #01061: is unoccupied and the head block signals atlaotlrl ends are at stop, and initiating the transmission of codes to both ends of the block by which 'the *trafiic relays are operated to supply current to the line circuit system at bothends. The resulting 'energizat'i-on of the line relays referred to, in the event the entire.

block is unoccupied, allows the train crew to -unlock the hand throw track switch and to reverse it to-permit "their train to enter-the block.

The .master directional "relay at the oflice is of the polar stick type or the like, arranged to be held in its last operated position when deenergized, and 'is governed by the code-controlled indication relays so that it is held deenergized following the reception'of a code indicating that a headblock signal is at clear, or of one indicating the presence of ;a train in the block.

One feature of myiinvention is the provision of means for maintaining the directional relay 'normally deenergized, its circuits being closed momentar'i'ly in response to the operation of a starting button or switch lock lever under the proper conditions as reflected by the code {indication system.

Another "feature o'fimy invention is the provision of -means {or rendering each starting button 'effective to initiate the transmission of codes to both-ends of the bl'ockfbut on'cehfor each operation of the master directional relay.

Other "features include means for preventing the operation of the :master directional relay by lever operation except when "codes are initiated for establishing *the corresponding traffic direction, and for enabling the operator to regain control of the master directional relay after it has been locked deenergized, in order to enable him to restore the original direction of traffic "if for any :reasonthe reversal of traffic direction is not required or cannot be effected due to a fault in the wayside circuits.

'Gther objects, purposes and features of my invention will be pointed out as the description proceeds.

I shall describe "one form of apparatus embodying my invention and shall then point out the novel features thereof in claims.

Referring to't'he accompanying drawings, Fig. 1 shows the circuits embodying my "invention contained in one section of the oflice control machine "of the centralized traffic control system, "including the control panels for two stations located at the opposite ends of a single 'track block arranged as indicated by the miniature track diagram at the top or the 'view, while Figs, 2A and 2B, taken also those for the control of the leaving signals ZL and ZR, :as well as those for other features, a

description of which is not needed for an understanding of my invention.

To simplify the drawings, in lieu of showing the various sources of "current for energizing the re- "lays, I have shown only their terminals, the posijtiverorisupplyiterminal being identified by the reference character B, and the negative or common return "terminal by the reference character C, in

each instance.

Similar reference characters refer to similar parts in each of the views.

"The code control system The code system employed for communication between the office and thewayside stations .corresponds generally to thatshown iniLetiters Patent of the United States "No. 2,229,249,, issued to me on January 21, 19.41,, andspecifically to a modification thereof shown in .an application .for LettersfP-atento'f .the Unitedl'States, SerialjNo. 49619.01, filed July 31, 1943, by Arthur 'P. Jadkel, now Patent ,No. 2,411,375, issued ,Nov. 16,, 19.46,, which system is describedina publication enti'tled.1\7l;anual 506-.A, of .theUnijon -Switch .andSignal Goof Swissvale, Pennsylvania? Consideration of the detailed mode of operation of the code system is not needed for an understanding .of my invention, and it jsdeemedsuific'ient to point out that the jcodesys'te-m provides seven channels for the transmission of controls from the olfice to a selected station, and seven other channels for the transmission of indications from any station to the ofiic.e,oII l y one station at a time, over a single line circuit, without interference. For simplicity, the various channels are designated by numbers and are represented herein by direct wire connections. Each control code transmitted from the ofiice isinitiated bythe manual .energization .of a starting relay, such as the relay 'OflST or O3 ST,Fi g. 1 of which one is provided ,for each ofiice panel. Each starting relay is picked up by the momentary closing of .a contact ,a or b of astaitingbutton ;l S'IB or 3STB or of the switch lock lever AWL. Lever 2WL is of the push-turn type, its contacts a'and b closing whenever its rotary contacts c and d are moved from .one operative position to another. Each starting relay initiates a code by closing its contact 0, and is held energized over a stick circuit until its code 02311 is transmitted, in the manner described in Patent No. 2,229,249.

Each control code includes a distinctive code call bywhich aselectorrelay fOl'S or O3Sfor the same panel, together with a delivery relay ID or 1313, Fig. "2A or at the corresponding field station No. I or No. .2, are energized, only :one panel and station at a time, thereby 'establislnng the control channels for communication between the selected panel and station. At the office "each channel is supplied with current or-not, depending upon .the control to be effected, and at'the selected station, a group of polar stick relays suchas'the relays 2RZFS, "Z'WLS, etc., are operated to:normal or reverse in accordance with the condition of a series of register relays lF2, lF l, etc., which are interposed in the channels. Of the seven control channels which the system provides, only channels 2, 4, '5 and l are shown herein.

The master directional relay by which the direction of traffic movements is governed is relay LP, Fig. 1. At station No. l, a traffic relay ZRFS, and at station No. 2, a trafiic relay ALFS, is operated over channel 2 by different codes to a position corresponding to that of relay LP. At station No. l, a switch control relay ZWLS for the hand throw switch 2W is controlled over channel 4, by a repeating relay ZWLP for the switch lock lever ZWL of Fig. 1, relay ZWLP also controlling the traffic relay ALPS over channel 2, in response to a code initiated by the operation of lever 2WL. At station No. l, the signal control relay ZRHS for signals ERA and ZRB is operable to reverse over channel 7, when the signal lever ZSG is in its right-hand reverse position, and at station No. 2, the signal control relay lLHS for signals lLA and iLB is operable to reverse over channel 5 when the signal lever 486 is in its left-hand reverse position.

The signaling system Considering now the wayside circuits of Figs. 2A and 2B, the head block signals as shown are of the searchlight type, each having an operating mechanism identified by the reference character G- prefixed by the signal designation, such as the mechanism iLAG for signal iLA. Each signal mechanism when energized in a normal or reverse direction conditions its signal to indicate proceed or caution and when deenergized, to indicate stop. The intermediate signals 2 I, 22, 23 and 24, which in the Young patent are of the searchlight type, are shown herein as of the color light type, having green, yellow and red lamps for indicating proceed, caution or stop. The lamp circuits for the intermediate signals as well as the mechanisms G for the head block signals are governed by polarized relays, each identified by the reference character I-ID prefixed by the designation of the corresponding signal. The signal relays 1-11) are all controlled over the reversible line circuit system, which as shown, is divided into three circuit sections corresponding to the three block sections, the circuit for each section including front contacts of the track relays TR for the adjacent track sections. Each signal relay HD is arranged to be energized in series with an ap--- proach relay AR. Each relay AR at an intermediate signal location governs the lighting of the correspondingly numbered signal in a well-known manner, while those at the head block locations govern the transmission of indications by the remote control system for indicating the occupancy of portions of the single track block.

Each intermediate signal relay such as relay 2 lHD when energized supplies current of normal polarity to the line circuit for the signal relay such as relay 23HD for the next signal in the rear, and has associated therewith the usual directional stick relay such as relay ZiS, which becomes e-nergized when a train passes the corresponding signal at proceed or caution and closes its front contacts to supply current of reverse polarity to the line circuit for the next section in the rear, and is held energized only until the associated signal relay HD is again energized. At the ends of the block, the polarity of the current supplied to the line circuit system is controlled by a pole changer relay such as relay ZLAPC or lRAPC controlled by the mechanism for the leaving signal 2LA or ARA over a circuit shown in the Young patent which is closed only when the signal indicates proceed, but which in other respects is similar to the circuit for the relay ZRAPC or ALAPC shown herein. The line circuit system is energized over a front contact of an approach locking relay 2RAS or 4LAS which is controlled in a conventional manner, as shown in the Young patent, by the stop indication relay ZRGP or iLGP for the adjacent entering signals and by suitable time locking apparatus, not shown herein, for preventing the clearing of the opposing signals except when traffic conditions are proper.

As shown, the contacts a and b of the trafllc relays ZRFS and 4LFS occupy their left-hand positions and the sections of the reversible line circuit system are thereby energized in cascade at their left-hand ends as required for traflic movements from right to left. More particularly, the left-hand contacts a and b of relay ZRFS connect terminals B and C of the local source of current at station No. I over contacts a and b of relay ZLAPC to the left-hand section of the line circuit system, whereby current is supplied over the front contacts of relay ZRAS and of the track relays lTR, ZTR and ZITR for the adjacent track circuits of the first section of the block, and back contacts of relays 22S and 22HD, to energize the signal relay ZlI-ID in series with the approach relay ZLAR. Relay ZlHD is energized in the reverse direction, as shown, to condition signal 2| to indicate caution, when signal 2LA indicates stop or caution, while relay 2IHD is energized in the normal direction to condition signal 2| to indicate proceed, when signal 2LA indicates proceed, in which case relay 2LAPC assumes its energized position. The closing of the front contacts a and b of relay ZlHD connects terminals B and C of the local source of current at the location of signals 2| and 22 to the intermediate section of the line circuit system, over back contacts of relay 2IS, the connection to terminal B including a back contact of relay 22HD, the winding of relay 2IAR and a front contact of relay 'ZITR. When relay 2 IHD is picked up, current of normal polarity is supplied over front contacts of the track relays 22TH, and 23TR of the track circuits for the intermediate section of the block and over front contacts a, b, c and d of relay ZNWP, and back contacts of relays 24S and 24HD, to energize the signal relay 23I-ID in the normal direction, in series with the approach relay 2 [AR and thereby condition signal 23 to indicate proceed. The closing of front contacts a and b of relay 23HD completes a similar circuit from terminals B and C of the source at the location of signals 23 and 2d, whereby current of normal polarity is supplied over front contacts of the track relays Z iTR, 4TB. and 3TB. for the third section of the block, and the left-hand contacts a and b of the traffic relay lLFS, to energize the signal relay GLHD in the normal direction in series with the approach relay 23AR. If now the signal control relay lLI-IS is operated to reverse, the closing of its contact a completes a circuit over front contact b of relay 4LHD whereby mechanism 4LAG is energized, over a contact N if switch 3W is normal, or mechanism lLBG is energized, over a contact R if switch 3W is reversed, each in the normal or reverse direction in accordance with the position of the polar contacts e and f of relay 4LHD, as will be readily apparent from the drawmg.

When the trafiic relays 2RFS and 4LFS are operated to close their right-hand contacts a 7 and it, the :signal' relays 2.! HD, and 11mm and the approach relays flLAR, MAR and 13KB, all release, holding signals 121,13JLA and ZLB at stop. "I hen relays MI-ID, 22E 13 and F-ZRHD lbecome energized in :cascade, :each in series with one of "the approach relays ZRAR, MAR and MAR, the circuits for the two directions being similar. signals 24 and 22 will then be conditioned to indicate --caution and proceed, respectively, and signal can or 2R3, depending upon the position ofsswitch IW, may be cleared by reversing relay 2RHS.

It will be understood that as a train governed by signal ALA, tor example, proceeds through the block, a directional stick relay 23s becoines energ'ized response tothe release of the track relay 23TH, during the release period of relay 2'3HD, over circuits similar to those shown "for relay fi l-S, and when the -ldloclr section in the rear of signal 23 is vacated, -fron't contacts a and "b of relay 23S connect terminals '3 and'C to the line circuit system to energize relay 4LHD in the reverse direction whereby signal @LA or 415B may e am be conditioned to indicatecaution. Similar-1y relay MS is energized upon the release of relay 2 l'-IR, during the release period of relay 2lI-ID, whereby relay '23 may he conditioned to indicate caution rto govern :a following train, or if relay "is released, to permit relay ZWAR to be energized as required to permi't a following train to enter the =b1oc-k over switch 2W reversed, as hereinafter described.

Outlying *track switch control The hand throw switch "2W is normally locked ment of which is limited by a locking dog on the magnet armature. Signals 22 and 2'3 whichgovern'train movementsover'switch 2W are prevented from clearing except when the switch 'isflocked normal by "including contacts of the switch indication relay 2NWPinthe'iiire circuit as already described. Relay '2NWP is normally energized over a circuit which includes a contact 'N controlled by switch 2W "which is closed only when the switch is .lUCkGd normal, and also includes contact Ml which is closed "only when .the hand throw lever 8 is locked normal by .the lock magnet EWLMQ segment 25, and contacts '4] and '49 are also held normally in the position shown by the bail 59 of "a padlock, which may be removedby the crewof 'a train after obtaining authority from the operator to unlock the switch. Segment '25 maythen be'moved a short distance to open the circuit including contact 49, releasing relay 'cNWRand to close contacts lit-41in the circuit for magnet 'ZWLM,

For a train movement from the main track to ee side track, magnet ZWIJM will then become energized, provided "the train has occupied the track section in approach to the switch, for .a

. time sufficient to complete the operation of a time element relay "TE controlled over a back contactof the track relay ZZTR.

For a train movement out of the side track, the central oifice operator will have cooperated Eloy moving his switch lever ZWL to the left or right, according to -the direction the train is to proceed after it enters lthe block, thereby initiating two control codes, one of which operates relay dill/"LES to reverse and also operates relay 2RFS to the :lett or right to correspond the postti n .of Zlever the other operating :relay 'ALFS to the right, so that terminals B .and 1C become connected :to the line circuit system at both ends, in lieu of at one end only, corresponding to .the exit .end LfOI the established traflic direction. If the block is unoccupied, current is supplied .over the line circuitsystem from both ends to energize the line relays and 2EAR at the switch location, provided contact 49 has been opened to release relay ZNWP and magnet :ZWLM may then be energized over contacts 46-41. This permits segment '25 to be moved to its full reverse position, which lever B is unlocked ,to permit :switch 2W to be'opera'ted to reverse.

In the foregoing, it has been assumed that the block is unoccupied, in which case the master directional relay LIP is free to respond to the switchlevenoperation and either direction of traffic movement may be established. Switch 2'! may :also be unlock-ed while the block is occupied, provided the train therein has passed the switch location. In this case relay LP is held deenergized, retaining the established "traffic direction, but one or the other of the two nodes transmitted in response to the reversal of lever ZWL will be eiiective to energize the line circuit system inthe rear of the train occupying'the-block, and when this train passes switch 2W, the release oi relay ENWP will'permit the energization of the corresponding one of the line relays 'ZWAR or ZEAR. The other of these relays will then become energized when the main line train vaca'tes the block section containing switch 2W, by current supplied to its line circuit over front contacts of the directional stick relay MS :or 245.

The code indication system Each indication code is initiated by the release of 'a norm-ally energized starting relay such as relay 1ST at station No. 1, which as shown by the circuits occurs either in response to a change in the position of one 'or more of the indicating relays or due to the operation of the-delivery relay II), when a control code is received. In each code initiated by relay ESl, a selector relay is at the station is energized along with a delivery relay O l'D in the corresponding office panel, in response to the station code call, to extend the indication channels -"9l5 from the selected station to the corresponding office panel. At station N0. '1, onlychanels w, M and i5 are shown herein, over which the indication stick relays ITK, :2RBK and 2RHK are "energized in response to the closing of back contacts of the corresponding indi- 'cating're'lays IIKS, ZRBP and ZR'GP at station No. 1. The release of the similar starting relay 3ST, *at station No. 2, initiates a code in which a selector relay 3S "and a delivery relay 03D are energized to control the indication stick relays LB-K-and over channels it, '52 and 1 4, and back contacts of relays .BTKS, 14LBP and *tIiGP, respectively.

Relays 11K and -3TK arethe usual trackindination relays which control the lamps lTKE and inthe OS sections of the track diagram, and which also usually control pen magnets a train aph as described 'in Patent No. 2,229,249. To prevent the loss of the indication of the arrival of ,a train at a station in the event the'tran'smission oi indications-is delayed and the train vacates the controlling track section before an indication of its occupancy is transmitted, .a storage relay such as relay ITKS is provided.

When a train enters the track section including switch FW andreleases the track relay ITR, the

opening of contact a of relay (TR releases relay ITKS, which relay by momentarily opening its contact releases the starting relay IS'I' to store the indication code for transmission as soon as the code line becomes available. Relay MSP is energized during the transmission of this code as described in Patent No. 2,229,249, and relay is reenergized during the transmission of this code. The contacts of relays MSP and 4ST in the circuit for relay ITKS serve to hold this circuit open until the code is fully transmitted, thereby insuring the energization of the track indication relay ITK over channel l0, even though its transmission occurs after the switch section is vacated and relay ITR is reenergized.

Relays ZRBK and iLBK are block indication relays which differ from the similarly designated relays of the hereinbefore referred to Young patent in that they are normally deenergized. Contacts c of these relays iointly control a block indication lamp BKE in the track diagram, which lamp is lighted to indicate the presence of a train in any section of the single track block.

When the right-to-left direction is set up, relay 4LBP, the release of which initiates the transmission of an indication code for energizing relay iLBK, is held energized, as shown, over the neutral contact a and the normal polar contact at of the signal relay 4LHD, only when the intermediate and right-hand block sections are both unoccupied, while relay ZRBP, therelease of which initiates the transmission of an indication code for energizing relay -2RBK, is held energized, as shown, over the left-hand contact a of relay 2WLS and front contact a of the approach relay ZLAR, only when the left-hand block section is unoccupied.

When the left-to-right direction is established, relay ZRBP is energized over contact 0 of relay ZWLS and contacts a and d of relay ZRHD provided the left-hand and'intermediate block sections are unoccupied, and relay 4LBP is energized over contact a of relay iRAR, provided the righthand block section is unoccupied.

A modification of this arrangement is required when the block contains more or less than three sections, a description of which herein is deemed unnecessary.

Lamp BKE is also lighted whenever the switch control relay ZWLS is operated to its reverse position, because contact 0 of relay ZWLS in the circuits for relay ZRBP is then open and relay ZRBP remains released to hold relay ZRBK energized regardless of block conditions.

The signal indication'relays ZRHK and ZLHK control lamps associated with the signal levers as in the Young patent hereinbefore referred to but to simplify the drawings these are not shown herein.

The traffic direction control system Referring to Fig. 1, the circuits for the master directional relay LP differ from those of the corresponding relay of the above-mentioned Young application and are arranged in a novel manner to include therein contacts 11 of the starting buttons I STB and 3STB as well as contacts of a normally deenergized direction locking relay LPS. When trafiic conditions as reflected by the indication relays are such as to allow the position of relay LP to be changed, back contacts b of the signal, track and block indication relays being closed, the operation of the signal lever G to its right-hand reverse position, or of lever 48G to its left-hand reverse position, completes a circuit at the lever contact b over contact b of relay LP iii) for energizing relay LPS, provided a change in the direction of traffic designated by relay LP is necessary in order to clear the signal controlled by the operated signal lever. When relay LPS picks up it becomes disconnected from its pick-up circuit by the operation of its contact a, and is held energized over a stick circuit having multiple connections to terminal B of the local source at back contacts a of the starting relays OIST and O3ST, so that relay LPS is held energized untilcontrol codes have been initiated, or stored for transmission, to the stations at both ends of the block.

If a signal lever is operated to reverse in preparation for the transmission of a control code which does not involve a change in the established trafiic direction, relay LPS remains released and the pressing of the starting button ISTB or 3STB then completes a circuit at its contact a only, whereby the associated starting relay 0 IST or 035T is energized, but when relay LPS is energized by the operation of a signal lever as described, the pressing of the starting button associated with that signal lever completes three other circuits, in addition. The closing of contact 0 of the operated button completes a circuit over contact 1 of relay LPS to energize a block repeating stick relay BKS, and the closing of contact cl of the operated button completes a circuit over contact I) or c of relay LPS for operating relay LP to the position designating the trafiic direction to be established, while the closing of contact b of the operated button completes a circuit over the reverse contact 0 of the operated signal lever and contact 9 or h of relay LPS for energizing the starting relay of the adjoining panel for the station at the opposite end of the block. It follows that two codes are initiated, for operating the traffic relays 2RFS and MLFS, respectively, in accordance with the open or closed condition of channel 2 as determined by contact 0 of relay LP so that these relays both assume positions corresponding to that of relay LP.

It will be seen that relay LP is free to be 0perated only when the block is unoccupied, as indicated when both of the block indication relays ZRBK and QLBK have been released by codes reflecting the energized condition of thereversible line circuit system. The interruption of the wayside circuits prevents the transmission of indications of the unoccupied block condition while the trafiic direction is being changed, but during this period, it is desirable to permit relay LP to remain operable to either position so that the original traffic direction can be restored if the operator so desires, or if the reversal cannot be eifected, due to a fault. This is accomplished by the provision of the block repeating relay BKS, which is energized along with relay LP as above described, and stores the block clear indication, in effect, to maintain relays LP and LPS operable, by closing its front contact I) in the circuits for these relays, until the wayside circuits are reestablished. When relay BKS picks-up, it closes circuits momentarily over its contacts d and e to pick up the block indication relays ZRBK and 4LBK locally, placing them in condition to be l- I versal; the circuits for. the direction indication lamp EFE' or. WEE. and: for the, block" indicationlamp BKE are held? open at back; contact of: relay BKS.

It? will be seen thatrelay 'LPS replaces thetwo relays EFK and WFK of: the: Young application, and or the Van Horn patent hereinbefore referred to, with respect to the control: oi? code transmission, but with: an improvect mode. of: operatioir, while relay BKS-Ireplaces relays and with respect to the control of the block indication relays. The: circuits fbr the relays LPS and BKS as disclosed herein are an provement upon those for similarly designated relays shown in an application for Letters Patent oi the United States, Serial No: 561,188; filed December 8'; 1944, by Frank T. Pascoe and Arthur L. Jerome, for Railway trafii'ccontrolling apparatus, which issued as Patent No; 2,411,387; on November 19', I946;

The operation of the switch lock lever ZWL also effective to' initiate the transmission of codes to both ends of the block, its contacts a and b closing momentarily to energize the starting relays OI'ST' and" 038T whenever lever ZW'L i's'- rotated from one operating position to another. Contact 0 of lever ZWll. controlsreI'ay'LP in accordance with the desired direction of traffic movement, and contact 0F oflever controls a repeating relay ZWLP by which the circuits governed" lloy relay ZWLP are interlocked by those controlled by the signal levers, that is, thecircuit for ZWLP includes backcontact of relay BKS and baclicontacts d" of relays ZRHK and MSHK, and the circuits" for'relays LPS and BKS include back'contacts e'and a of"- relay ZWLP'.

Operation- 1 shall first assume that the system is set up for the right-to l'eft direction. and: in itsnormal condition as shown, with Iamp-WFE lighted but with signals ALA: and 4 13B at-stop; and shall trace the operations for clearing signal" ZRA.

The operator moves lever ZSG to the right, which completes acircuitfrom terminal 3 at bacli contact 5' of relay 2RBK over back contacts b of relays iLBK, ITK, Z'RHK and lTiHK; the right-hand contact bof" signal lever 25G, the normal or right-hand contact a of lever A'SG, left-hand contact I) of'rel'ay' LP, back contact a and winding of relay LPS to terminal C at back; contact 2* of" relay 2-WLP. Relay LES picks up and completes a stick circuit at its own front contact at extending to terminallB at back contacts 0' of: relays O l-8'1 and OBS-T.

The operator then: presses lbutton'. LSTB, en ergizi'ng relay O'I'S'I" over the button contact a,

and: energizing relay 038T over the circuit inclhding the button contact 12', the right-hand contact 0: of lever: Z SGJ and contact 57 ct relay BPS; also energizing relay BKS over the circuit extending: frornv terminal. B at: contact a. of relay ZWLP; contact 1% of relay LPS' and contact 0 of which relays thus assume positions corresponding tosthe occupied block condition and are-heldenergized' over their stick circuits including their own front contacts aand the back contacts of: the delivery relays OID and 03D, respectively, and by closing their front contacts I), complete a sticic circuit including (back contacts (1 of, relays ITK and 3TK and front contact a of relay BKS for holding relay BKS energized. The opening of back contact 0 of relay BKSextinguisheslamp WFE and maintains lamps and BKE dark; While the closing of'front contact b of relay BKS prepares a circuit for restoring relay LP which includes its lowerwinding and the open contacts b of lever lSG and d of button 38133 and is also open: at contact 0' of relay LPS'; the circuit for which as traced above is now open: at contact b of relay LP;

The closing of front contacts c oirelaysOlST and 038T initiates the transmission of control codes to the corresponding stations Nos. l and 2 at the opposite ends of the block, as described in Patent No. 2,229,249. In the code initiated by relay OIST, relays 01S and ID are operated, and since the connection fromv contact 0 of relay LP to channel 2: over contact a of relay O-[S is open, relay IFZ, Fig. 2A, is; not operated and relay ERFS is operated to close its right-hand contacts aand b, by relay ID. Channel 4 is open, so that relay ZWLS is operated to the left, but channel i is energized over contact g of relay OHS, contact 01 of lever ZSG' and contact 0 of relay LP, so that relay- ZRHS is operated to the right. In the code initiat'e'd'by relayOBST, relays 03S and 3]] are operated, energizing channel 2 only, over contacts 0 of relay LP and contact 6 of: relay 038, to operate-relay' iLFS to: the right.

Relays ZBFSz and ALPS" in theirright-hand positions reverse the direction of: energization of the line: circuit system as: hereinhefore described. Q- LBP ispicked up by relay QRAR, and relay" ZJEBPby relay and since contact a of relay ZRHS. is closed, relay ZRHD energizes mechanism. ZRAG to. clear signal ZRA, and to release relay" ZRGP.

These: operationsv result in theinitiation of one or more indication codes from each station, whereby." relays ZRBK and 413K are released, thereby releasing relay BKS- and lighting lamp EFE: to indicate the trafiic direction established, and relay ZRHK becomes energized to indicate the clearing of the signal and opens its back contact I) to lock relay LP reversed;

Usually these codes will all be transmitted before the train: governed bysignal ZRLA enters the block; but if the code system controls a large number of stations and the trafll'c is heavy, it may happen that the train will pass signal 2RA at clear and enter the block before the system has an opportunity to transmit the indication code by which relay ZRHK is energized and relay ZRBKreleased; In this case, the first code received from" station No. l-,, following the transmission. of: the control codes for reversing the traffic'direction; will be the OS code, energizing relay even though the train has vacated the OS sectionbefore this code istransmitted, due to itsstorage by relay ITKS; The opening of contact b'of relay ITK. locks relay LP; and the opening of contact d oi relay" ITK releases relay BKS', thereby rendering relay ZRB-K effective, provided it: is maintained energized bythiscode, to light lamp-BKE to indicate the occupied block condition, and to hold relays: LP: and LPS deenergized. Lamp EFE,v also becomes lighted to indicate the established direction of trafflc as in the preceding example.

It will be seen that lamp BKE indicates whether or not the block is occupied only when lamp EFE or WFE is lighted to indicate that the corresponding direction of trafiic is established, and that while the traffic direction is being established all three lamps are dark.

It may be that the operator after having initiated the reversal of trafiic as above described will wish to restore the original traffic direction, due to a change in orders or in case it is found that the reverse direction cannot be set up due to a fault. He will first assure himself that the entering signal is at stop with its control relay ZRHS normal, by transmitting a code for operating relay ZRHS to normal. The operation of the delivery relay ID by this code releases relay IST thereby initiating the transmission of an indication code, in which, if signals ZRA and ZRB are at stop, channel I is deenergized, so that relay ZRHK remains released.

If a train has already entered the block at this time, under the control of signal ZRA or 2RB, this indication code will cause relay ITK to become energized over channel Ill, releasing relay BKS to light lamps EFE and BKE, and relay ZRBK or 4LBK will remain energized to hold relay LP reversed and relay LPS released until the train vacates the block.

If relay ITK is not energized by this indication code, the operator may restore the original direction of traific by moving the signal lever ZSG to its normal center position and then moving lever 45G to the left, thereby energizing relay LPS over the circuit extending from terminal B at front contact I) of relay BKS, over back contacts b of relays ITK, 3TK, ZRHK and ALHK. left-hand contact b of lever 48G, contact a of lever ZSG, right-hand contact b of relay LP, back contact a and winding of relay LPS to terminal C at contact 6 of relay ZWLP. The operator will then press button 3STB, energizing relays 038T and OIST and the lower winding of relay LP, thereby operating relay LP to the left, initiating the transmission of a code to station No. I in which channel 2 is energized, and one to station No. 2 in which channel 5 is energized. The eifect of these codes is to clear the signal 4LA or 4LB, as will'be readily understood, resulting in the transmission of indication codes for releasing relays ZRBK and ALBK, thereby releasing relay BKS lighting lamp WFE. and energizing relay ZLHK to indicate the clearing of signal ILA, thereby locking relay LP in the position shown.

I shall now trace the operations involved in unlocking switch 2W, assuming that the rightto-left traffic direction is set up as shown, and that the crew of a train on the siding at switch 2W has communicated with the operator by telephone, requesting authority to enter the block and to move their train in the opposite direction, that is, toward the right.

The operator moves lever ZWL to its righthand position, leaving the signal levers ZSG and lSG both in their normal positions, as shown. Contacts a and b of lever ZWL close momentarily, energizing the starting relaysOlST and O3ST to initiate the transmission of control codes to stations at both ends of the block. The closing of contact d of lever ZWL energizes relay 2WLP over the circuit extending over back contacts at of relays ZRI-IK and lLHK to terminal B, at back contact b of relay BKS, and the closing of the right-hand contact 0 of lever ZWL energizes the 14 upper winding of relay LP, over front contact b of relay 2WLP and back contacts b of the indication relays, so that relay LP is operated to its right-hand position to correspond with the position of lever 2WL.

In the code transmitted to station No. l, channel 2 is not energized, but channel 1 is energized over contact at of relay ZWLP, and in the code transmitted to station No. 2, channel 2 is energized over contact 0 of relay ZWLP and also over the right-hand contact 0 of relay LP. Consequently these codes serve to operate each of the relays 2WLS, ZRFS and 4LFS to the right, in which case, as will be clear from Figs. 2A and 2B, the line circuit system is supplied with current at both ends, energizing relays ZIHD and 24I-ID and thereby conditioning signals 2| and 24 to indicate caution, and if segment 25 is operated by the train crew to open contact 49 and thereby release relay 2NWP, the line relays ZWAR and ZEAR will both become energized to complete a circuit for the lock magnet ZWLM to permit switch 2W to be unlocked. The approach relays 2 LAR and ARAR are both energized, likewise the indicating relay 4LBP, but relay ZRBP remains released due to the opening of contact 0 of relay ZWLS. The block indication relay ZRBK is therefore energized over channel l4, opening the circuits for relays LP and LPS and lighting lamp BKE.

After the operator has been advised that the switch has been unlocked, he restores lever 2WL to its normal center position. This again closes contacts a and b of lever ZWL momentarily to initiate the transmission of codes to both ends of the block. Relay ZWLP is released by the opening of contact a of lever ZWL, and it follows that in response to these codes relay ZWLS is operated to the left and relay ZRFS to the right, relay lLFS remaining in its right-hand position. Relays ZLAR, ZlI-ZD and ZWAR release, relay ZRBP remains released and relay ZRBK energized, so that lamp BKE remains lighted.

When the train enters the main track, relay ZEAR releases, and when switch 2W is again locked in its normal position by the train crew, relay ZNVVP becomes reenergized. As the train passes signa1 24, relays MHD, lRAR and ALBP release and the directional stick relay 248 becomes energized, and an indication code is initiated by relay 4LBP by Which the block indication relay 4LBK is energized. When the train vacates the intermediate block section, relay ZZHD becomes energized in the reverse direction, energizing relay ZRI-ID in the normal direction, energizing relay ZRBP which initiates a code by which relay ERBK is released, but lamp BKE remains lighted due to the energization of relay lLBK, until the train vacates the block. Signal 22 is conditioned to indicate caution, and the operator may move lever ZSG tothe right and transmit a code to station No. l to reverse the signal control relay ZRHS if he desires, to permit signal EPA or ZRB to be cleared for a following train.

Assuming next that with the right-to-left traflic direction set up as shown, that the switch 2W is to be unlocked to permit a train to enter the block and tomove in the established direction, toward the left. In this case the operator moves lever ZWL to the left, energizing relay ZWLP and the lower winding of relay LP, holding relay LP in its left-hand position, and initiating codes by which relays 2WLS and AlLFS are operated to the right by relay EWLP, and relay held in its left-hand position by relayLP, energizing the t 'linacirouiitsystem at both. ends so that switch- 2W may." he lmlocked', as in: the.- preceding example.

Since-1hr this instance; the. traffic directionis notchangeithese: operationsmay be carried out while the block is occupied by a precedingv train", proyided. it'- hasvacatedl th'erb'lock section containhag". switch: Thus it the left-hand section is occupied by a. trai'm moving: toward theleft, the directionali stick relay" 219: will be; energized in lieu) of relay ZJIHD, to supply current to relay.

in. response? to'tlre: release: of: relay ZNWP, the operations in other. respects being similar to those already described.

Although. I1 have herein shown and described orrly'one: formaot. apparatusembodying my: invenit is understood that. various changes and modifications may be made: therein within the scope: or the appended. claims without departing fromthespirit and scope ofmiy invention.

Having thus described; by invention, what I claim 1:. Railway trafiic' controlling apparatus located at a: central oifice. for controlling traffic in a stretch). of: single; track: railway equipped with. an entering signal? at each end governed by a signallcontrollrelay and also governed in accordance with trafllc conditions: by a System of" reversible circuits cont-rolled? jointly by traific relays at the ends or the": stretch; comprising atwo position directional relay for-designating trailic direction, a signal lever for each" signal, a starting button for each levereffective: when operated to actuate astarting relay associated therewith to initiate the-transmission of'a codereflecting the positions of the associated signal lever and of said directionallre'lay; to which. the signalcontrol and trafiic relays; at the corresponding end of the stretch are responsive; signal. indication relays controlled by the signals for indicating their condition and block indication relays controlled. by said system of circuits for indicating when the stretch is unoccupied, a. normally deenergized direction looking relay, a. block. indication repeating relay, a

traffic direction which is the opposite to-that requiredlirrorder to :clear the signal controlled by the operatedrlever, circuits closed by the operation' of the starting button for the operated lever when the. direction locking relay is energized for operating said'direction'al relay to the position required to establish the corresponding'traffic direction, for energizing said block indication repeating relay and for actuating the starting relays associated with? both signal levers to thereby initiate the transmission. of codes to both ends of the block, a circuit for maintaining said directional locking relay energized after the directional relay is operated only until both starting relays are actuated, means controlled by said block indicationrepeating relay when energized for renderin said block indication relays ineffective tox-control said direction locking relay, and a circuit for maintaining said block indication repeating relay energized only until the block indication relays are again controlled by said system of circuits to indicate that the stretch is unoccupied.

2. Railway trafiic controlling' apparatus locatedat-a centraloffice. for controlling trafiic in a arseam stretclr of single trackrailway equipped with an entering signal at each end" governed by a-signal control relay' and also governed inaccordance with traflic' conditions by a system of reversible circuits controlled. jointly by traffic relays at the ends of the stretch, comprising a two position directional relay for designating. traflic direction, a signal lever for each: signal, a starting button for each lever effective. when operated to actuate a starting relay associated therewithto initiate the transmissionofa-code reflecting the positions of the associated signal lever and of saiddirectional relay,..to-which the" signal control and trai fic relays at the corresponding: end of the stretch are responsive, signal indication relays controlled by the signals: for indicating their condi tiers and block indication relays controlled by said system: of circuits forindicating; when: the stretch is. unoccupied, a normally deenergizeddirection locking: relay, a: circuit-for energizing said direction. locking relay closed upon the operation of one signal lever or the other to its signal clearing position including contacts of the-indication relays which when. closed indicate that the sigrials are at stop andthat the stretch is: unoccupied, and also including a. contact of the directional relayclosed only whensuch relay occupies a. position designating the traffic direction which is. the opposite tothat-required' in order to clear the signal controlled by the operated lever, circuits closed bythe. operation of the starting button for theoperated lever when the direction locking relay is energized for operating said: directional relay to the position required to establish the corresponding directioniand for actu ating; the starting relays-associated with-both'si'gnal levers, and a' circuit for maintaining said direction locking relay energized after the. directional relay is operated only until both: starting relays are actuated.

3.- Railway trafiiccontrolling apparatus located at a central ofiice for controlling traffic. in a stretch of single track railway equipped with a reversible signal system; comprising a two positiondirectional relay for designating traiiic' directiorr, a normally deenergi'zed direction locking relay, circuits including front contacts'oi' saiddirectionlocking relay and manually controllable contacts operable to' different positions for operating said" directional" relay to corresponding positions to designate one traflic direction or another; block indication relays at the ofiice controlled by trafficconditions to indicate when the stretch is unoccupied; a pick-up circuit for said direction locking relay including contacts of said block indication relays which when closed indicat'e that the block is unoccupied, and" also including said manually controllable contacts and contacts of said directional relay closed only in non-corresponding positions, manually controllable relay' means for setting up said" signaling system: in the direction indicated by said" directional relay rendered effective by the energization of said direction locking relay, anda stick circuit for holding said direction locking relay energized following the reversal of said directional relay only'until'said manually controllable relay means is actuated.

4. Direction selecting apparatus for controlling traific movements over a stretch of single track railway equipped with a reversible signaling system, a twoposition: directional relay at a control oilice for designating trafiic direction, a code communication system for" transmitting manually initiatedcontrol. codeszreflecting the position of said directional relay to stations at the ends of the stretch to control said signaling system, and for automatically transmitting indication codes from said stations reflecting the condition of occupancy of the stretch to control indication relays at the office, a normally deenergized direction locking relay, circuits includingmanually operable contact meansfor operating said directional relay from either of its two positions to the other position effective only when said direction locking relay is energized, and a circuit for energizing said direction locking relay including said manually operable contact means and contacts of said directional relay ,closed in non-corresponding positions and also including contacts of said indication relays which when closed indicate that the stretch is not occupied.

5. Direction selecting apparatus for controlling traffic movements over a stretch of single track railway equipped with a reversible signaling system, a two position directional relay at a control office for designating traffic direction, a code communication system for transmitting manually initiated control codes refiecting the position of said directional relay to stations at the ends of the stretch to control said signaling system, and for automatically transmitting indication codes from said stations reflecting the condition of occupancy of the stretch to control indication relays at the office, a normally deenergized direction locking relay, circuits including manually operable contact means for operating said directional relay from either of its two positions to the other position efiective only when said direction locking relay is energized, a pick-up circuit for energizing said direction locking relay including .said manually operable contact means and contacts of said directional relay closed in non-corresponding positions and also including contacts of said indication relays which when closed indicate that the stretch is not occupied, and. a stick circuit arranged to hold said direction locking relay energized only until said code system is manually initiated to transmit codes refiecting the position of said directional relay to both said stations.

6. Direction selecting apparatus for controlling trafiic movements over a stretch of single track railway equipped with a reversible signaling system, a two position directional relay at a control ofiice for designating traffic direction, a code communication system for transmitting manually initiated control codes reflecting the position of said directional relay to stations at the ends of the stretch to control said signaling system, and for automatically transmitting indication codes from said stations reflecting the condition of occupancy of the stretch to control indication relays at the ofiice, a normally deenergized direction locking relay, circuits including manually operable contact means for operating said directional relay from either of its two positions to the other position efiective only when said direction locking relay is energized, a normally deenergized repeating relay, a circuit for energizing said direction locking relay including said manually operable contact means and contacts of said directional relay closed in non-corresponding positions and also including contacts of said indication relays which when closed indicate that the stretch is not occupied, and in parallel with said indication relay contacts, a front contact of said repeating relay, a pick-up circuit for said repeating relay closed in response to the manual initiation of a code when said direction locking relay is energized, circuit "means effective when said locking relay and repeating relay are energized for locally operating said indication relays to the positions they assume in response to received codes indicating that the stretch is occupied, and a'stick circuit for the repeating relay closed by theindication relays for maintaining the repeating relay energized until a code is received indicating that the stretch is unoccupied.

. 7. Direction selecting apparatus for controlling traflic movements over'a stretch of single track railway equipped with a reversible signaling system, said stretch including afshortdetector sec-'- tion at each end,'a'twoposition directional relay at a control ofiice for designating trafiic direction, a code communication system for transmitting manually initiated control codes reflecting the position of said directional relay to stations at the ends of the stretch to control said signaling system and for automatically transmitting indication codes from each station to control a track indication relay to indicate the condition of occupancy of the corresponding detector section and to control a block indication relay in accordance with the condition of said signaling system to indicate the condition of occupancy of a portion of said stretch, the condition of the remainder of which is indicated by a similar block indication relay controlled by codcs transmitted from the other station, a direction locking relay controlled by said indication relays, a repeating relay controlled by said direction locking relay, circuits including a manually operable contact means for operating said directional relay to either of its two positions effective only when said direction locking relay is energized, a circuit for energizing said direction looking relay including said manually operable contact means and contacts of said directional relay closed in non-corresponding positions and including contact of said block indication relays which when closed indicate that the entire stretch is unoccupied, and in parallel with said indication relay contacts, a front contact of said repeating relay, said circuit also including contacts of said track indication relays each of which when closed indicates that the corresponding detectpr section is unoccupied, circuit means effective when said locking relay and repeating relay are energized for locally operating said block indication relays to the positions they assume in response to received codes indicating that the stretch is unoccupied, a stick circuit for the repeating relay closed by the indication relays for maintaining the repeating relay energized until a code is received which indicates either that the stretch is unoccupied or that a train has entered one of the detector sections, and means at each station for storing a code indicating the occupancy of the adjacent detector section until such code is transmitted.

8. Direction selecting apparatus for controlling trafi'lc movements over a stretch of single track railway having an entering signal at each end, and a reversible system of circuits for controlling one signal or the other in accordance with traific conditions in the stretch, a signal lever for each signal and a two position directional relay for controlling the direction of energization of said system of circuits, located at a control oflice, a code communication system for transmitting manually initiated control codes to stations at the ends of the stretch each of which reflects the position of said directional relay and of the lever ,fgr thesignal at the station t which. the code is .;transmi-tted, and, 'f.0.1- automatically transmitting indication codes. from said stations. reflectlingthe condition of occupancy oi the stretch, as indicated said, system of circuits when energized, to. control, indication relays at the omce, a, normally deenergized direction locking relay,,a circuit controlled by each leverincluding afront contact. of. said direction locking relay closed when uch lever is operatedv to reverse to): clearing, its. signal, tor operating said directiQnalyrelay to the. position, for energizing said circuitisystem in the. corresponding direction, and. a. circuitfor energizing said. direction lockreIay including saidreversed signal lever 2% contact andha, contact of.;said-..d'-irectional relay closed only in the: position corresponding .tc-zthe oppositedirection cf traffic movements in said stretch, and also including contacts oi-said-v indication relays. whiclmwhen chased indicatethat the stretch isunoccupied and innarallelrwith said indication relay contacts, a. normally men contact which is closed in. response totheoperation 01 said directiont locking'relayand o en-ed when. said indicationrelays. are againoperated by codes received from the stations to, indicate that. the stretch isunoccupied'.

LLOYD V.v

No referencescited. 

